There are bearing housings for a turbocharger, which are provided with a cooling structure using water or air to protect from a high temperature environment caused by exhaust gas a supporting part of a shaft which integrally connects a turbine rotor to a compressor.
For instance, there is a cooling structure configured to promote a flow of cooling water in a water jacket by connecting an inlet and an outlet of a circulation water passage to the water jacket and providing a partition board at the connection part to partition the passage into an inlet side and an outlet side (Patent Document 1). There is another cooling structure in which a top part partitioning wall is provided at a top part of a cooling water jacket and an inlet and an outlet for cooling water are formed in both sides with respect to the partitioning wall (Patent Document 2).
According to FIG. 1 and FIG. 4 of Patent Document 1, a water jacket 7 is formed in a center housing 6, and a water passage flange 1 is attached to the center housing 6 to face the water jacket 7. Further, in this water passage flange, a water inlet passage 2 for introducing cooling water into the water jacket 7 and a water outlet passage 3 for discharging the cooling water from the water jacket 7 are provided, and a partition board 5 is provided in the water passage flange 1 to project inside the water jacket 7 and separate a water inlet passage 2 and a water outlet passage 3.
According to FIG. 1 and FIG. 2 of Patent Document 2, a cooling water jacket 31 is formed in a bearing housing 3 to have a loop shape surrounding the entire circumference of the turbine shaft 5, and the top part partitioning wall 32 is formed on the cooling water jacket 31 to partially close the loop shape of the cooling jacket 31, and the inlet 33 and the outlet 34 of cooling water are formed in the bearing housing 3 to communicate with the cooling water jacket 31 at a position where the top part portioning wall 32 is interposed between the inlet 33 and the outlet 34